Improvement in steam safety-valves



Patented June 12., 1877.

" UNITED STATES l PATENT FFIE.

WILLIAM B. MACK, O F BOSTON, MASSAGHUSETTS.

lnmnaovi-:MENI` |N STEAM SAFETY-VALVES,

Specification forming part of Letters Patent No. i9 1,@71, dated June 12,1877; application led i February 17, 1877.

To all whom t may concern Be it known that I, WILLIAM B. MACK, of Boston, in the county of Suffolk and State of Massachusetts, have invented certain I1nprovements in Steam Safety-Valves, of which the following is a specification In the accompanying drawing, forming a part of this specification, Figure l represents a transverse vertical central section of a valve embodying my improvement. Fig. 2 represents a top view of the valve-seat, the valve being removed; and Fig. 3 represents a sectional view of an old form of valve-seat.

This invention relates to that class of steam safety-valves in which a surface is formed on the valve outside ofthe ground-joint for the escaping steam to act against, and thereby a'ssist in holding the valve open, and it relates more particularly to valves ofthe above-named class in which this surface is formed in an adjustable lipped flange, as in the patent of Patrick Mooney, August 25, 187 4, No. 154,509.

The object of my invention is to improve the construction of the valve-seat of a valve of the above-named class in such manner that the operation of the valve shall be more efficient and satisfactory, and that the escape of steam shall be attended with less noise than ,heretofore. To these ends my invent-ion consists in providing the valve-seat outside of the groundjoint with an annular upwardly-projecting lip or flange of less diameter than the downwardly-projecting lip or ange of the valve, and of such height a's to project above the plane of the lower` edge of the said lip or ange when the latter is closed, as I will now proceed to describe.

In the drawings, A represents. the valve, having the adjustable portion A', which is provided with a downwardly-projecting lip or flange, a, aslin the patent of Mooney above referred to, the valve being otherwise of the usual construction. B represents the valveseat, which is provided with an upwardly-projecting marginal rim or flange, j', and an inner upwardly-projecting lip or ange, L, which is located between the ground-jointof the valveseat and the rim f. rIhe lip l Vis of less diameter than the lip a of the valve, and is of such height and diameter that when the valve is closed the upper edge of the lip l will project above the plane of the lower edge of' the lip a, and a narrow annular space will exist be tween the inner surface of the lip a and the outer surface of the lip l, the adjacent sides of the lips a l being vertical, and therefore parallel'. The rim f is considerably higher thanv the lip l, as shown in Fig. l.

rIhe surfaces of the valve-seat on each side of the lip l are preferably dat and in the same plane, and the under surface of the adjustable ange A is also dat. By this construction an annular chamber or space, c, is formed, which is bounded partly on one side by the lip Z, the latter constituting a barrier or cushion, over which the escaping steam must pass. The close proximity of the lip l to the lip a of the valve, renders it impossible for the steam to escape rapidly until the lower edge of the lip a is raised above the plane of the upper ledge of the lip L. Hence it will be seen that when the valve is opened the escaping steam, being confined in the space c, will readily raise the valve until an opening is created between the lips a l equal in area to the opening be tween the ground-joints of the valve and seat. It will also be seen that the adjustability of the lip a, in connection with the lip l, enables the valve to be easily regulated as to the degrec of pressure required to lift it to its vutmost extent.

lt has been usual heretofore to provide the outer portion of the valve seat with an annular groove or depression adapted to receive the lip of the valve, or to make the valve-seat of such diameter that the lip a of the valve will entirely inclose the upper edge' of the seat, as shown in Fig. 3. This construction necessitates the forming of a deeper groove or annular recess in the Valve to make the space c than in my construction, and this deep groove or recess causes the escaping steam to to the vaive, in combination with said piane In testimony whereof I have signed my and lip, substantially as and for the purpose name to this specification in the presence of described. two subscribing witnesses.

2. A valve-seat: having a plane extending 1 from the point of escape ot' steam, and pro- WILLIAM B' MAOK vided with a projecting lip to direct; the steam Witnesses upward, and an intermediate lip, as and for the CARROLL D. WRIGHT,

purpose set forth. PETER W. FRENCH. 

